Automotive lift systems have been long known in the prior art. However, during approximately the last fifteen years, the primary system used to perform maintenance and service upon and from underneath of automotive vehicles has changed from an in-ground post lift system to a so-called above-ground system.
The appeal of the above-ground lift system is largely in its environmental advantages. More particularly, the U.S. Environmental Protection Agency and the U.S. Occupational Safety and Hazards Agency have imposed strict and costly regulations relating to most forms of on-site excavation that include the use or storage of toxic chemicals in the ground. In the prior art of in-ground post-lift systems, it was necessary to store hydraulic, and other potentially hazardous materials underground. Accordingly, and primarily as a response to governmental regulation, the trend in the last fifteen years has been strongly away from in-ground post-lift systems and in the direction of above-ground lift systems.
Among the latter category, a type of lift known as a parallelogram lift has appeared. The term parallelogram is employed because, when viewed from the side, the structure thereof exhibits the configuration of a parallelogram. This style of lift is unique in the above-ground market in that it has eliminated the need for posts. Posts are undesirable in that they take-up room and create potential obstruction to workers. Further, the elimination of posts has brought about a saving of space, and are more efficient in function than prior art in-ground systems. However, the parallelogram lift has encountered market resistance in the United States due to reasons of its newness of design and regarding concerns in respect to its safety, notwithstanding the fact that the parallelogram-style lift is, by most standards of analysis, the safest lift manufactured in the United States today. Also, existing parallelogram systems make use of longitudinal on-ground elements, between the posts, which inhibit left-to-right access to the vehicle.
Prior art representative of such parallelogram automotive lift systems comprise the following:
U.S. Pat. No. 3,330,381 (1967) to Halstead, entitled Vehicle Lift; U.S. Pat. No. 4,447,042 (1984) to Maiser, entitled Vehicle Lift; and Canadian Patent No. 1,236,449 (1988) to Rossato, entitled Lifting Ramp.
It is a goal of the present invention to effect the elimination of torsion bars, that is, cross-connecting or cross-coupling elements between left and right rows of hydraulic lifting legs that are present in parallelogram lifts, and which impede front and rear access to the elevated vehicle.
It is another goal to provide a parallelogram system having improved left-to-right access, by eliminating longitudinal on-ground elements.